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NetBSD/sys/netccitt/hd_input.c

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/* $NetBSD: hd_input.c,v 1.15 2001/04/13 23:30:19 thorpej Exp $ */
/*
* Copyright (c) 1984 University of British Columbia.
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Laboratory for Computation Vision and the Computer Science Department
* of the University of British Columbia.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)hd_input.c 8.1 (Berkeley) 6/10/93
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <net/if.h>
#include <netccitt/hdlc.h>
#include <netccitt/hd_var.h>
#include <netccitt/x25.h>
#include <netccitt/pk_extern.h>
static void frame_reject __P((struct hdcb *, int, struct Hdlc_iframe *));
static void rej_routine __P((struct hdcb *, int));
static void free_iframes __P((struct hdcb *, int *, int));
/*
* HDLC INPUT INTERFACE
*
* This routine is called when the HDLC physical device has
* completed reading a frame.
*/
void
hdintr()
{
struct mbuf *m;
struct hdcb *hdp;
struct ifnet *ifp;
int s;
static struct ifnet *lastifp;
static struct hdcb *lasthdp;
for (;;) {
s = splnet();
IF_DEQUEUE(&hdintrq, m);
splx(s);
if (m == 0)
break;
if (m->m_len < HDHEADERLN) {
printf("hdintr: packet too short (len=%d)\n",
m->m_len);
m_freem(m);
continue;
}
if ((m->m_flags & M_PKTHDR) == 0)
panic("hdintr");
ifp = m->m_pkthdr.rcvif;
/*
* look up the appropriate hdlc control block
*/
if (ifp == lastifp)
hdp = lasthdp;
else {
for (hdp = hdcbhead; hdp; hdp = hdp->hd_next)
if (hdp->hd_ifp == ifp)
break;
if (hdp == 0) {
printf("hdintr: unknown interface %p\n", ifp);
m_freem(m);
continue;
}
lastifp = ifp;
lasthdp = hdp;
}
/*
* Process_rxframe returns FALSE if the frame was NOT queued
* for the next higher layers.
*/
if (process_rxframe(hdp, m) == FALSE)
m_freem(m);
}
}
int
process_rxframe(hdp, fbuf)
struct hdcb *hdp;
struct mbuf *fbuf;
{
int queued = FALSE, frametype, pf;
struct Hdlc_frame *frame;
struct sockaddr *sa = (struct sockaddr *) hdp->hd_pkp;
frame = mtod(fbuf, struct Hdlc_frame *);
pf = ((struct Hdlc_iframe *) frame)->pf;
hd_trace(hdp, RX, fbuf);
if (frame->address != ADDRESS_A && frame->address != ADDRESS_B)
return (queued);
switch ((frametype = hd_decode(hdp, frame)) + hdp->hd_state) {
case DM + DISC_SENT:
case UA + DISC_SENT:
/*
* Link now closed. Leave timer running
* so hd_timer() can periodically check the
* status of interface driver flag bit IFF_UP.
*/
hdp->hd_state = DISCONNECTED;
break;
case DM + INIT:
case UA + INIT:
/*
* This is a non-standard state change needed for DCEs
* that do dynamic link selection. We can't go into the
* usual "SEND DM" state because a DM is a SARM in LAP.
*/
hd_writeinternal(hdp, SABM, POLLOFF);
hdp->hd_state = SABM_SENT;
SET_TIMER(hdp);
break;
case SABM + DM_SENT:
case SABM + WAIT_SABM:
hd_writeinternal(hdp, UA, pf);
case UA + SABM_SENT:
case UA + WAIT_UA:
KILL_TIMER(hdp);
hd_initvars(hdp);
hdp->hd_state = ABM;
hd_message(hdp, "Link level operational");
/* Notify the packet level - to send RESTART. */
(void) pk_ctlinput(PRC_LINKUP, sa, NULL);
break;
case SABM + SABM_SENT:
/*
* Got a SABM collision. Acknowledge the remote's SABM via UA
* but still wait for UA.
*/
hd_writeinternal(hdp, UA, pf);
break;
case SABM + ABM:
/* Request to reset the link from the remote. */
KILL_TIMER(hdp);
hd_message(hdp, "Link reset");
#ifdef HDLCDEBUG
hd_dumptrace(hdp);
#endif
hd_flush(hdp->hd_ifp);
hd_writeinternal(hdp, UA, pf);
hd_initvars(hdp);
(void) pk_ctlinput(PRC_LINKRESET, sa, NULL);
hdp->hd_resets++;
break;
case SABM + WAIT_UA:
hd_writeinternal(hdp, UA, pf);
break;
case DM + ABM:
hd_message(hdp, "DM received: link down");
#ifdef HDLCDEBUG
hd_dumptrace(hdp);
#endif
(void) pk_ctlinput(PRC_LINKDOWN, sa, NULL);
hd_flush(hdp->hd_ifp);
case DM + DM_SENT:
case DM + WAIT_SABM:
case DM + WAIT_UA:
hd_writeinternal(hdp, SABM, pf);
hdp->hd_state = SABM_SENT;
SET_TIMER(hdp);
break;
case DISC + INIT:
case DISC + DM_SENT:
case DISC + SABM_SENT:
/* Note: This is a non-standard state change. */
hd_writeinternal(hdp, UA, pf);
hd_writeinternal(hdp, SABM, POLLOFF);
hdp->hd_state = SABM_SENT;
SET_TIMER(hdp);
break;
case DISC + WAIT_UA:
hd_writeinternal(hdp, DM, pf);
SET_TIMER(hdp);
hdp->hd_state = DM_SENT;
break;
case DISC + ABM:
hd_message(hdp, "DISC received: link down");
(void) pk_ctlinput(PRC_LINKDOWN, sa, NULL);
case DISC + WAIT_SABM:
hd_writeinternal(hdp, UA, pf);
hdp->hd_state = DM_SENT;
SET_TIMER(hdp);
break;
case UA + ABM:
hd_message(hdp, "UA received: link down");
(void) pk_ctlinput(PRC_LINKDOWN, sa, NULL);
case UA + WAIT_SABM:
hd_writeinternal(hdp, DM, pf);
hdp->hd_state = DM_SENT;
SET_TIMER(hdp);
break;
case FRMR + DM_SENT:
hd_writeinternal(hdp, SABM, pf);
hdp->hd_state = SABM_SENT;
SET_TIMER(hdp);
break;
case FRMR + WAIT_SABM:
hd_writeinternal(hdp, DM, pf);
hdp->hd_state = DM_SENT;
SET_TIMER(hdp);
break;
case FRMR + ABM:
hd_message(hdp, "FRMR received: link down");
(void) pk_ctlinput(PRC_LINKDOWN, sa, NULL);
#ifdef HDLCDEBUG
hd_dumptrace(hdp);
#endif
hd_flush(hdp->hd_ifp);
hd_writeinternal(hdp, SABM, pf);
hdp->hd_state = WAIT_UA;
SET_TIMER(hdp);
break;
case RR + ABM:
case RNR + ABM:
case REJ + ABM:
process_sframe(hdp, (struct Hdlc_sframe *) frame, frametype);
break;
case IFRAME + ABM:
queued = process_iframe(hdp, fbuf, (struct Hdlc_iframe *) frame);
break;
case IFRAME + SABM_SENT:
case RR + SABM_SENT:
case RNR + SABM_SENT:
case REJ + SABM_SENT:
hd_writeinternal(hdp, DM, POLLON);
hdp->hd_state = DM_SENT;
SET_TIMER(hdp);
break;
case IFRAME + WAIT_SABM:
case RR + WAIT_SABM:
case RNR + WAIT_SABM:
case REJ + WAIT_SABM:
hd_writeinternal(hdp, FRMR, POLLOFF);
SET_TIMER(hdp);
break;
case ILLEGAL + SABM_SENT:
hdp->hd_unknown++;
hd_writeinternal(hdp, DM, POLLOFF);
hdp->hd_state = DM_SENT;
SET_TIMER(hdp);
break;
case ILLEGAL + ABM:
hd_message(hdp, "Unknown frame received: link down");
(void) pk_ctlinput(PRC_LINKDOWN, sa, NULL);
case ILLEGAL + WAIT_SABM:
hdp->hd_unknown++;
#ifdef HDLCDEBUG
hd_dumptrace(hdp);
#endif
hd_writeinternal(hdp, FRMR, POLLOFF);
hdp->hd_state = WAIT_SABM;
SET_TIMER(hdp);
break;
}
return (queued);
}
int
process_iframe(hdp, fbuf, frame)
struct hdcb *hdp;
struct mbuf *fbuf;
struct Hdlc_iframe *frame;
{
int nr = frame->nr, ns = frame->ns, pf = frame->pf;
int queued = FALSE;
/*
* Validate the iframe's N(R) value. It's N(R) value must be in sync
* with our V(S) value and our "last received nr".
*/
if (valid_nr(hdp, nr, FALSE) == FALSE) {
frame_reject(hdp, Z, frame);
return (queued);
}
/*
* This section tests the IFRAME for proper sequence. That is, it's
* sequence number N(S) MUST be equal to V(S).
*/
if (ns != hdp->hd_vr) {
hdp->hd_invalid_ns++;
if (pf || (hdp->hd_condition & REJ_CONDITION) == 0) {
hdp->hd_condition |= REJ_CONDITION;
/*
* Flush the transmit queue. This is ugly but we
* have no choice. A reject response must be
* immediately sent to the DCE. Failure to do so
* may result in another out of sequence iframe
* arriving (and thus sending another reject)
* before the first reject is transmitted. This
* will cause the DCE to receive two or more
* rejects back to back, which must never happen.
*/
hd_flush(hdp->hd_ifp);
hd_writeinternal(hdp, REJ, pf);
}
return (queued);
}
hdp->hd_condition &= ~REJ_CONDITION;
/*
* This section finally tests the IFRAME's sequence number against
* the window size (K) and the sequence number of the last frame we
* have acknowledged. If the IFRAME is completely correct then it is
* queued for the packet level.
*/
if (ns != (hdp->hd_lasttxnr + hdp->hd_xcp->xc_lwsize) % MODULUS) {
hdp->hd_vr = (hdp->hd_vr + 1) % MODULUS;
if (pf == 1) {
/* Must generate a RR or RNR with final bit on. */
hd_writeinternal(hdp, RR, POLLON);
} else
/*
* Hopefully we can piggyback the RR, if not we will
* generate a RR when T3 timer expires.
*/
if (hdp->hd_rrtimer == 0)
hdp->hd_rrtimer = hd_t3;
/* Forward iframe to packet level of X.25. */
fbuf->m_data += HDHEADERLN;
fbuf->m_len -= HDHEADERLN;
fbuf->m_pkthdr.len -= HDHEADERLN;
fbuf->m_pkthdr.rcvif = (struct ifnet *) hdp->hd_pkp;
#ifdef BSD4_3
fbuf->m_act = 0;/* probably not necessary */
#else
{
struct mbuf *m;
for (m = fbuf; m->m_next; m = m->m_next)
m->m_act = (struct mbuf *) 0;
m->m_act = (struct mbuf *) 1;
}
#endif
pk_input(fbuf);
queued = TRUE;
hd_start(hdp);
} else {
/*
* Here if the remote station has transmitted more iframes
* then the number which have been acknowledged plus K.
*/
hdp->hd_invalid_ns++;
frame_reject(hdp, W, frame);
}
return (queued);
}
/*
* This routine is used to determine if a value (the middle parameter) is
* between two other values. The low value is the first parameter the high
* value is the last parameter. The routine checks the middle value to see if
* it is within the range of the first and last values. The reason we need
* this routine is the values are modulo some base hence a simple test for
* greater or less than is not sufficient.
*/
bool
range_check(rear, value, front)
int rear, value, front;
{
bool result = FALSE;
if (front > rear)
result = (rear <= value) && (value <= front);
else
result = (rear <= value) || (value <= front);
return (result);
}
/*
* This routine handles all the frame reject conditions which can arise as a
* result of secondary processing. The frame reject condition Y (frame
* length error) are handled elsewhere.
*/
static void
frame_reject(hdp, rejectcode, frame)
struct hdcb *hdp;
int rejectcode;
struct Hdlc_iframe *frame;
{
struct Frmr_frame *frmr = &hd_frmr;
frmr->frmr_control = ((struct Hdlc_frame *) frame)->control;
frmr->frmr_ns = frame->ns;
frmr->frmr_f1_0 = 0;
frmr->frmr_nr = frame->nr;
frmr->frmr_f2_0 = 0;
frmr->frmr_0000 = 0;
frmr->frmr_w = frmr->frmr_x = frmr->frmr_y =
frmr->frmr_z = 0;
switch (rejectcode) {
case Z:
frmr->frmr_z = 1; /* invalid N(R). */
break;
case Y:
frmr->frmr_y = 1; /* iframe length error. */
break;
case X:
frmr->frmr_x = 1; /* invalid information field. */
frmr->frmr_w = 1;
break;
case W:
frmr->frmr_w = 1; /* invalid N(S). */
}
hd_writeinternal(hdp, FRMR, POLLOFF);
hdp->hd_state = WAIT_SABM;
SET_TIMER(hdp);
}
/*
* This procedure is invoked when ever we receive a supervisor frame such as
* RR, RNR and REJ. All processing for these frames is done here.
*/
void
process_sframe(hdp, frame, frametype)
struct hdcb *hdp;
struct Hdlc_sframe *frame;
int frametype;
{
int nr = frame->nr, pf = frame->pf, pollbit = 0;
if (valid_nr(hdp, nr, pf) == TRUE) {
switch (frametype) {
case RR:
hdp->hd_condition &= ~REMOTE_RNR_CONDITION;
break;
case RNR:
hdp->hd_condition |= REMOTE_RNR_CONDITION;
hdp->hd_retxcnt = 0;
break;
case REJ:
hdp->hd_condition &= ~REMOTE_RNR_CONDITION;
rej_routine(hdp, nr);
}
if (pf == 1) {
hdp->hd_retxcnt = 0;
hdp->hd_condition &= ~TIMER_RECOVERY_CONDITION;
if (frametype == RR && hdp->hd_lastrxnr == hdp->hd_vs
&& hdp->hd_timer == 0 && hdp->hd_txq.head == 0)
hd_writeinternal(hdp, RR, pf);
else
/*
* If any iframes have been queued because of
* the timer condition, transmit then now.
*/
if (hdp->hd_condition & REMOTE_RNR_CONDITION) {
/*
* Remote is busy or timer condition, so only
* send one.
*/
if (hdp->hd_vs != hdp->hd_retxqi)
hd_send_iframe(hdp,
hdp->hd_retxq[(u_char)hdp->hd_vs],
pollbit);
} else /* Flush the retransmit list first. */
while (hdp->hd_vs != hdp->hd_retxqi)
hd_send_iframe(hdp,
hdp->hd_retxq[(u_char)hdp->hd_vs],
POLLOFF);
}
hd_start(hdp);
} else
frame_reject(hdp, Z, (struct Hdlc_iframe *) frame); /* Invalid N(R). */
}
/*
* This routine tests the validity of the N(R) which we have received. If it
* is ok, then all the iframes which it acknowledges (if any) will be
* freed.
*/
bool
valid_nr(hdp, nr, finalbit)
struct hdcb *hdp;
int nr;
int finalbit;
{
/* Make sure it really does acknowledge something. */
if (hdp->hd_lastrxnr == nr)
return (TRUE);
/*
* This section validates the frame's N(R) value. It's N(R) value
* must be in syncronization with our V(S) value and our "last
* received nr" variable. If it is correct then we are able to send
* more IFRAME's, else frame reject condition is entered.
*/
if (range_check(hdp->hd_lastrxnr, nr, hdp->hd_vs) == FALSE) {
if ((hdp->hd_condition & TIMER_RECOVERY_CONDITION) &&
range_check(hdp->hd_vs, nr, hdp->hd_xx) == TRUE)
hdp->hd_vs = nr;
else {
hdp->hd_invalid_nr++;
return (FALSE);
}
}
/*
* If we get to here, we do have a valid frame but it might be out
* of sequence. However, we should still accept the receive state
* number N(R) since it has already passed our previous test and it
* does acknowledge frames which we are sending.
*/
KILL_TIMER(hdp);
free_iframes(hdp, &nr, finalbit); /* Free all acknowledged
* iframes */
if (nr != hdp->hd_vs)
SET_TIMER(hdp);
return (TRUE);
}
/*
* This routine determines how many iframes need to be retransmitted. It then
* resets the Send State Variable V(S) to accomplish this.
*/
static void
rej_routine(hdp, rejnr)
struct hdcb *hdp;
int rejnr;
{
int anchor;
/*
* Flush the output queue. Any iframes queued for
* transmission will be out of sequence.
*/
hd_flush(hdp->hd_ifp);
/*
* Determine how many frames should be re-transmitted. In the case of
* a normal REJ this should be 1 to K. In the case of a timer
* recovery REJ (ie. a REJ with the Final Bit on) this could be 0.
*/
anchor = hdp->hd_vs;
if (hdp->hd_condition & TIMER_RECOVERY_CONDITION)
anchor = hdp->hd_xx;
anchor = (anchor - rejnr + 8) % MODULUS;
if (anchor > 0) {
/* There is at least one iframe to retransmit. */
KILL_TIMER(hdp);
hdp->hd_vs = rejnr;
while (hdp->hd_vs != hdp->hd_retxqi)
hd_send_iframe(hdp, hdp->hd_retxq[(u_char)hdp->hd_vs],
POLLOFF);
}
hd_start(hdp);
}
/*
* This routine frees iframes from the retransmit queue. It is called when a
* previously written iframe is acknowledged.
*/
static void
free_iframes(hdp, nr, finalbit)
struct hdcb *hdp;
int *nr;
int finalbit;
{
int i, k;
/*
* We need to do the following because of a funny quirk in the
* protocol. This case occures when in Timer recovery condition
* we get a N(R) which acknowledges all the outstanding iframes
* but with the Final Bit off. In this case we need to save the last
* iframe for possible retransmission even though it has already been
* acknowledged!
*/
if ((hdp->hd_condition & TIMER_RECOVERY_CONDITION) && *nr == hdp->hd_xx && finalbit == 0) {
*nr = (*nr - 1 + 8) % MODULUS;
#if 0
printf ("QUIRK\n");
#endif
}
k = (*nr - hdp->hd_lastrxnr + 8) % MODULUS;
/* Loop here freeing all acknowledged iframes. */
for (i = 0; i < k; ++i) {
m_freem(hdp->hd_retxq[(u_char)hdp->hd_lastrxnr]);
hdp->hd_retxq[(u_char)hdp->hd_lastrxnr] = 0;
hdp->hd_lastrxnr = (hdp->hd_lastrxnr + 1) % MODULUS;
}
}
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